Tottenham suffered their third consecutive Premier League defeat as they lost at home to Chelsea, who moved up to sixth in the table.
Jorginho’s penalty, after Eric Dier had fouled Timo Werner, gave Chelsea a deserved lead in the first half.
Werner, who headed wide in the opening minute, was denied a goal by an excellent block from Serge Aurier.
Tottenham’s Erik Lamela had a chance to equalise but his shot was pushed wide by Chelsea goalkeeper Edouard Mendy.
Spurs’ Carlos Vinicius also headed wide late on as the hosts were beaten for the third time in eight days, after losing 3-1 at home to Liverpool on 28 January and then 1-0 at Brighton on Sunday.
It was also the first time Tottenham boss Jose Mourinho had lost back-to-back home games in his managerial career.
Chelsea midfielder Jorginho told BT Sport: “We knew it would be a hard game in the derby but we worked hard, created chances and deserved the win.
“We just needed to keep working hard in the second half. The results will come.
“The best thing is that we prepared, we worked and we need to think about the next game.”